Drain-clear container for aqueous liquid pharmaceutical preparations



Dec. 23, 1952 H. ROSENBLUM 2,622,598

DRAIN-CLEAR CONTAINER FOR AQUEOUS LIQUID PHARMACEUTICAL PREPARATIONS Filed March 8 1951 I TRANSPARENT BOTTLE OPAQUE AQUEOUS- Z VEHICLE LIQUID PHARMACEUTICAL, mg. penicillin in aqueous suspension THIN TRANSPARENT FILM 0F SILICONE AND SILICONE ANTI- FOAM AGENT ATTORNEY Patented Dec. 23, 1952 DRAIN-CLEAR CONTAINER FOR AQUEOUS LIQUID PHARMACEUTICAL PREPARATIONS Harold Rosenblum, Hackensack, N. J assignor to Premo Pharmaceutical Laboratories, Inc.,

South Hackensack, N. J a corporation of New York Application March 8, 1951, Serial No. 214,561

2 Claims.

My invention relates to drain-clear containers for aqueous liquid pharmaceutical preparations (hereinafter referred to as aqueous pharmaceuticals) The present invention is an improvement of the drain-clear container shown, described and claimed in U. S. Letters Patent No. 2,504,482 issued April 18, 1950 to the assignee of the instant application.

As pointed out in said patent, coating the internal surface of a dispensing container with a thin, transparent water-repellent silicone film will cause the container to drain clear when an aqueous-vehicle liquid pharmaceutical preparation is dispensed therefrom. A typical preparation of such character is procaine penicillin in aqueous suspension. It has been observed, that although such a container has the ability to drain clear, there is a tendency for a film to cling to the inside of the container for a short time, thereby somewhat delaying the time in which it drains clear. A container treated in accordance with said patent and filled with an aqueous suspension of procaine penicillin takes about thirty seconds to drain clear. In the event that all the pharmaceutical preparation is withdrawn rapidly from the container, although the film temporarily clinging to the walls of the container is extremely thin and therefore constitutes but a very small percentage of the containers original contents, the presence of the film does represent some wastage and may leave the doctor unsure that he has secured a correct dose from a container which is not supposed to have any film left on its walls.

Accordingly, it is an object of the present in vention to provide for aqueous base pharmaceuticals a container whose interior surface has a film which not only will permit the container to drain clear, but to drain clear very rapidly, for example, in as little as five seconds.

Other objects of my invention will in part be" obvious and in part will be pointed out hereinafter.;

In the accompanying drawing in which is shown one of the various possible embodiments of my invention, the single figure is an elevation view, partially broken away, of a bottle having a film such as described hereinabove.

I believe that the tendency to leave on the walls of the container for a short period of time, in the order of a half a minute, a residual film of the containers contents is due to the presence of bubbles in the preparation after the same has been shaken prior to aspirating the pharmaceutical into a hypodermic syringe. Upon occasion, these bubbles are visible, particularly when the-- In general, I carry out my invention by incorporating in the water-repellent film which is provided on the internal surfaces of the container, a foam inhibitor, and more particularly a silicone foam inhibitor.

More specifically, my invention is achieved by providing a pharmaceutical container with an internal surface which has been rendered waterrepellent by silicone treatment and which also has been treated, preferably at the same time, with a silicone antifoam agent. By pharmaceutical container, I refer to any type of vessel which can receive and hold an aqueous-vehicle pharmaceutical preparation. Typical of such containers are vials, bottles, ampoules, hypodermic syringes, pipettes and burettes. By silicones," I refer to organo-polysiloxanes, i. e. organo-silicon oxide polymers. By antifoam agen I refer to a composition which has the ability to prevent or rapidly dispel foam when incorporated in the liquid wherein the foam is to be suppressed.

In practicing the invention, a silicone and a silicone antifoam agent carried in a vaporizable liquid vehicle are applied to the internal surfaces to be treated, as, for example, by rinsing the inside of a container with a liquid containing a silicone and a silicone antifoam agent dissolved or dispersed in such liquid. Thereafter, the liquid is evaporated, thus leaving a very thin, transparent solid film of the silicone and silicone antifoam agent. Said film is water-repellent so that when a container thus treated, and containing an aqueous-vehicle pharmaceutical preparation is emptied, the film which normally would remain on its internal surfaces contracts into globules which fall toward the bottom of the container and leave the walls clean. Moreover, I have discovered that such film has the property of very substantially speeding up the contraction of the film into globules. a marked speed up of the contraction of the film actually takes place where the coating on the inside of the container includes an antifoam agent in addition to a water-repellent agent. Thi increased speed of clear-draining occurs whether a surface active agent is present in the pharmaceutical composition or not, but is more marked where such an agent has been added.

More specifically, my invention is achieved by I have observed that. such dissolving a silicone and a silicone antifoam agent in an organic solvent, such as chloroform or ether. The composite fluid, solvent and solutes, is introduced into a container. Thereafter, the composite fluid is drained out, leaving a film thereof on the inner wall of the container. The solvent in this film is permitted to evaporate. Optionally, evaporation may proceed at room temperatures, and satisfactory results are secured in such fashion. Even better results are obtained where the solvent not only is evaporated, but the residual film of the silicone and the silicone antifoam agent is heat-treated to bake the same. Such heat treatment consists in elevating the temperature of the container to any point above room temperature and below a temperature at which the silicone or the silicone antifoam agent vaporizes from the container surface. In general, the higher the temperature employed, the less time is required for baking. The actual temperature used is not critical. It is believed that the layer of silicone and silicone antifoam agent is molecularly fused to the walls of the container, particularly when the container is glass.

Organo-polysiloxanes which function satisfactorily in the practice of my invention are of the formula where n is any integral number and R is any single alkyl or aryl group or combination thereof, that is to say different R groups may be combined in a single organo-polysiloxane to add up to. the total number of R groups required by the formula. The alkyl groups may be saturated or unsaturated and examples thereof are methyl, ethyl, propyl, butyl, amyl, hexyl, heptyl, octyl, decyl, dodecyl, vinyl and allyl. Examples of the aryl groups are phenyl, toluyl and naphthyl. Satisfactory silicones are:

Hexamethyl disiloxane (CH3) sSizO Dodecamethyl pentasiloxane (CH3)12S1504 Methylphenylpolysiloxane where a: is any integral number less than 2n+2.

Other satisfactory silicones have the same formulae except that for the methyl groups in the first two silicones and for the methyl and phenyl groups in the last silicone any other aryl or alkyl groups can be substituted.

It may be mentioned that in commercial silicones 11. reaches very high values and the chain is so long that the values of n are not used to denote the compounds, but rather physical properties are employed for this purpose. The physical property commonly employed is viscosity. I have found silicones of all viscosities to be operable in the practice of my invention-even as high as 100,000 centistokes.

Silicone antifoam agents which function satisfactorily in the practice of my invention are mixtures of alkyl silicones such as described above and unsubstituted silica, an example of the same being a physical mixture of methyl polysiloxane and finely divided silica. A silicone antifoam agent such as described is characterized by its ability, when added to a liquid, to prevent or suppress foam, it being noted that as already mentioned said antifoam agent in accordance with my invention is not added to the liquid pharmaceutical preparation, but, as a solid,

forms part of a coating for the internal surface 7 of, a pharmaceutical container.

4 By way of example and without limiting my invention thereto, the following constitutes a specific embodiment of a composite fluid with which I have secured very good results:

1 part by weight of methyl silicone fluid viscosity 50 centistokes 0.1 part by weight of silicone antifoam agent Enough chloroform to make up parts by weight.

Satisfactory results have been obtained with the silicone antifoam agent varying from as little as 0.0005 to 0.2 part by weight in the foregoing formulation. A suitable baking time is one-half hour at 300 0., or nine hours at 180 C.

Where other silicones or silicone antifoam agents are employed, the same percentages by weight can be used as well as the same baking temperature and time provided that the temperature does not exceed that at which the silicone or silicone antifoam agent will vaporize from the container surface.

Inasmuch as the film of water repellent silicone and silicone antifoam agent is transparent, the best visual results are obtained when the container likewise is made of transparent material such as glass, for example. A film applied in the manner described is so thin that its thickness is measured in hundreds of molecules.

A typical aqueous pharmaceutical preparation which the container is adapted to dispense is a procaine penicillin in aqueous suspension, said pharmaceutical containing a slight amount, e. g. 0.1% by weight of a surface-active agent to maintain the stability of the suspension after the same has been agitated. Suitable surfaceactive agents that may be employed are: sorbitan polyoxyalkylene monolaurate, sorbitan polyoxyalkylene palniitate, sorbitan polyoxyalkylene stearate, sorbitan polyoxyalkylene oleate, sorbitan monolaurate, sorbitan palmitate, sorbitan stearate, sorbitan oleate, and sorbitan trioleate.

If it is desired to reuse a container whose internal surface has been treated in accordance with the foregoing process, the same may be washed either with water, or soap and water, without affecting the applied film.

In the drawing I have shown a pharmaceutical container constituting a transparent glass bottle l0 whose internal surface has been coated, as aforesaid, with a thin transparent film I2 of a silicone and a silicone antifoam agent. The interior surface thereby is rendered water-repellent and is characterized by its ability to prevent or suppress foam in a liquid aqueouspharmaceutical preparation held by the container. As noted heretofore, the film is extremely thin. However, its thickness has beenv increased, as illustrated in the drawing, so that the same can be seen and a reference numeral applied thereto. The bottle is filled with an opaque aqueous-vehicle liquid pharmaceutical preparation l4, such for example, as procaine penicillin in aqueous suspension, the same containing a slight amount of a surface-active agent.

If desired, the silicone and the silicone antifoam agent maybe applied separately to the internal surfaces to be treated. Either the silicone or the silicone antifoam agent can be appliedv first and the manner of individual application can be the same as the manner of joint application outlined hereinabove.

It thus will be seen that I have provided a container which achieves the several objects of my invention and is well adapted to meet the conditions of practical use.

As various possible embodiments might be made of the above invention, and as various changes might be made in the embodiment above set forth, it is to be understood that all matter herein described and. shown in the accompanying drawings is to be interpreted as illustrative and not in a limiting sense.

Having thus described my invention, I claim as new and desire to secure by Letters Patent:

1. A clear-draining dispensing container of transparent material filled with an aqueousvehicle liquid pharmaceutical preparation, said container having on its internal surface a thin transparent film of a silicone and a silicone antifoam agent whereby when said pharmaceutical preparation is dispensed, the container will drain clear rapidly.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 2,504,482 Goldman Apr. 18, 1950 2,523,281 Currie Sept. 26, 1950 2,573,637 Bender Oct. 30, 1951 

